Synthesis and in vitro test of C-methylcalix[4]resorcinaryl octacinnamate as the sunscreen has been conducted. The C-methylcalix[4]resorcinaryl octacinnamate was synthesized in 2 steps. They were synthesis of C-methylcalix[4]resorcinarene via acid catalyzed condensation of resorcinol and acetaldehyde, followed by estherification using cinnamoyl chloride and pyridine catalyst. The characterization of the target molecule was performed by infra red spectrophotometer, proton-NMR, carbon-NMR and mass spectromether. The sunscreen activity test was conducted by spectroscopic method and MTT-assay. Spectroscopic analysis (UV) showed that the target molecule absorbed the dangerous ultraviolet radiation between 280 and 320 nm (UV B) wave length with the maximum absorption at 290 nm (ε = 31.535 M-1 cm-1). The MTT-assay indicated that the IC50 of C-methylcalix[4]resorcinaryl octacinnamate is 12.006 ppm. The sunscreen activity of C-methylcalix[4]resorcinaryl octacinnamate is stronger than commercial sunscreen Intersun (IC50 = 18.235 ppm).